Comparative analysis on resistance profiling along tapered semiconductor nanowires: multi-tip technique versus transmission line method
Comparative analysis on resistance profiling along tapered semiconductor nanowires: multi-tip technique versus transmission line method
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DOI：
10.1088/1361-648x/aa801e
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发表时间：
2017-10-04
影响因子：
2.7
通讯作者：
Hannappel, Thomas
中科院分区：
文献类型：
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作者：
Naegelein, Andreas;Liborius, Lisa;Hannappel, Thomas
与平面结构相比，纳米线(NWS)上的接触电阻和路径电阻等与掺杂相关的值的检测仍然是相当具有挑战性的。不幸的是，通常使用且建立良好的TLM(传输线测量)设置显示出一些缺点。复杂的初步准备步骤和欧姆接触的必要性限制了对某些半导体材料的研究。同时测定具有未知分布的接触和路径电阻使得对像锥形纳米线这样的复杂结构的分析非常具有挑战性。我们的方法是使用多尖端扫描隧道显微镜(MT-STM)作为四点探针器，它允许以更高的空间分辨率来研究独立的纳米线。在这里，使用的测量设置允许电流注入和电位测量的局部分离，从而高精度地确定路径电阻。用锥形p掺杂的GaAsNW对两种工艺进行了比较。由于MT-STM对轴向掺杂分布的评估相当简单，但在TLM测量中必须引入修正因子来计算比电阻和转移长度。通过对同一NW样品的两种方法测量结果的比较，证明了MT-STM测量的精密度和准确度。我们发现了一个一致的结论，即这两种方法都具有优势；然而，MT-STM被确定为更精确的设置，它能够提供额外的表征能力，如表面、温度或光相关测量。
The detection of doping dependent values like contact-and path resistances along nanowires (NWs) still proves to be rather challenging compared to planar structures. Unfortunately, the usually used and well established TLM (transmission line measurement) setup exhibits some drawbacks. Complex preliminary preparation steps and the necessity of ohmic contacts limit the investigation to certain semiconductor materials. The simultaneous determination of contact- and path resistances with an unknown distribution makes an analysis on complex structures like tapered nanowires very challenging. Our approach is the utilization of a multi-tip scanning tunneling microscope (MT-STM) as a four point prober, which allows the investigation of freestanding nanowires with an increased spatial resolution. Here, the used measurement setup allows a local separation of current injection and potential measurement and thus a highly precise determination of path resistances. Tapered p-doped GaAs-NWs were used to compare both techniques. Whereas the evaluation of the axial doping profile by MT-STM was rather simple, correction factors had to be introduced for the TLM measurement to calculate the specific resistances and transfer length. By comparing the results of both methods for the very same NW-sample, the precision and accuracy of MT-STM measurements was demonstrated. We found an agreement, which allows the conclusion that both methods exhibit advantages; however the MT-STM was determined as the more precise setup, which enables additional characterization capabilities, such as surface, temperature or light dependent measurements.